Look, taken by itself this post is reasonable. You’re right, engi is one of the hardest classes to play well, not that it’s not possible.
That said, I saw you also posted this thread about bots being better than players. This makes me think that maybe you’re the one not making enough of an effort to avoid disablers (every single one can be consistently avoided with the correctly timed side dodge and/or push), and overall not meshing well with human players. Don’t take that harshly, it’s absolutely reasonable to not be able to dodge them every time only 4 weeks into the game.
Generally speaking, human players do more damage and take less damage than the bots when the team is playing well together, even if they won’t always make as much of an effort to rescue you (although, a good player always makes a judgment call. If they can rescue you without taking too much damage themselves, they should. Rescuing disabled or downed teammates is a skill I feel like I particularly try to be good at).
Obviously you’ll all die faster if the team isn’t playing nice with each other at all.
This matters because when you get to Cata and Cata+, the bots simply won’t keep up compared to human teammates unless you really put in work. It’s important to find the right balance of the “being able to solo any situation yourself” mindset so that everyone is killing what they should fast with the “gotta help watch my teammates’ backs” mindset. It sounds like you might still be stuck in “Gatling gun go brr against everything” mode which obviously won’t work in Cata. It’s a situational tool for elites, specials, and monsters and only used for hordes when absolutely safe.
The main advantage engi has over other classes like ranger vet after all, is the fact that you always have a long range capable sniping weapon that you can use anytime as long as it’s safe to charge it up. That means you can bring something like Torpedo, Drakegun, or Drakefire pistols as your secondary. You should be using your drakegun at hordes instead of your ult so you don’t shoot your teammates, and if you didn’t bring one, just try using your melee against hordes like everyone else unless you see a perfect bottleneck that none of your teammates are already standing in. I guarantee you’ll see some improvement.